Composite remediation agent for organic contaminated soil as well as preparation method and application of composite remediation agent

Abstract

The invention provides a preparation method of a composite remediation agent for organic contaminated soil, which comprises the following steps: S1, uniformly mixing straw powder, pyroligneous liquor,an enzyme component and rice washing water, adding water for wetting, and carrying out fermentation culture in a biochemical incubator; S2, adding rice washing water and microbial components into themixture fermented in the step S1, and putting the mixture into a biochemical incubator for fermentation culture; S3, uniformly mixing biochar, a ferrous chloride solution, sodium selenite and a fertilizer, and granulating after the biochar is completely adsorbed; S4, adding the biochar particles obtained in the step S3 into the mixture fermented in the step S2, and uniformly stirring the mixtureto obtain the composite remediation agent for the organic contaminated soil. The remediation agent for the organic contaminated soil, provided by the invention, has a good remediation effect on the soil, is particularly very effective for degrading organic matters and pesticide residues in the soil, can also reduce the content of heavy metals such as mercury, lead and cadmium in the soil, effectively improves the comprehensive capacity of the soil, and ensures the safety of foods.

Description

technical field [0001] The invention relates to the technical field of soil remediation, in particular to a composite remediation agent for organic polluted soil, a preparation method and an application thereof. Background technique [0002] In recent years, with the continuous acceleration of the industrialization process, the unreasonable exploitation of mineral resources and their smelting discharge, the long-term sewage irrigation and sludge application to the soil, the atmospheric deposition caused by human activities, and the application of chemical fertilizers and pesticides have caused Soil pollution is serious. [0003] At present, the soil remediation technologies for heat-sensitive pollutants such as organic pollution and heavy metal mercury mainly use gas phase extraction, chemical leaching, thermal desorption technology, biological methods, etc. However, it is difficult to degrade the contaminated sites with high toxicity and high pollution levels by biological ...

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Problems solved by technology

[0004] For organic polluted soil sites, the traditional chemical oxidation technology uses strong oxidants such as ozone, hydrogen peroxide, potassium permanganate, Fenton's reagent, persulfate, percarbonate, etc. The lower the oxidation potential, the more difficult it is to degrade organic pollutants According to the strength of redox potential, it can be seen that Fenton's reagent has the strongest oxidative property, but it is extremely unstable during use, easy to decompose by itself, and uncontrollable, so it needs to be prepared and used immediately, and because it is difficult to inject holes when it is implemented on site. It will cause uneven distribution of soil injection, and the effect of oxidation and degradation of pollutants is not good

Ozone is a gas. It is injected into the soil layer by drilling holes. It has a better effect on sandy soil, but the effect is not obvious on cohesive soil with poor ventilation.

[0005] In the relevant literature, microwaves and sodium percarbonate are used to decompose low-molecular, medium-boiling organic matter polluted soils. The desorption rate is not high, and the oxidation potential of percarbonate is not too high. After making a solution, it is easy to decompose by itself. Not obvious, the general removal rate is more than 40%, the desorption effect on heat-sensitive heavy metal mercury is not strong, the removal efficiency of mercury is not high (about 22.2%), and the scope of application is not wide

[0006] In the relevant literature, Fenton’s reagent is used to catalyze the oxidation reaction to remediate organically polluted soil. The desorption effect of low molecular organic acids is slightly obvious, but the reaction can only have better activity when the pH value is close to 3, and the effect Relatively single, the expected degradation effect cannot be achieved for some organic substances, and the TOC removal rate does not exceed 60%; at the same time, the chemical reagent H that needs to be consumed 2 o 2 A large amount of iron powder is used, the catalytic efficiency is low and the actual catalytic effect is not obvious, and it is difficult to mix the iron powder into the soil, which is easy to cause iron pollution, and only local degradation may occur, and for heat-sensitive heavy metal pollution

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